Found it. A snippet in another language bundle (KSP, recently added) was causing it.  

I didn't know that snippets all bundles  are simultaneously active. Is this norma behaviour or is this a bug or configuration option? 

thanks
- bruno

On May 15, 2014, at 9:28, Bruno Degazio <lifemusic@sympatico.ca> wrote:

Whenever I type a ':' (colon) character Textmate automatically inserts an equals sign. At first I thought something changed in my language bundle (Forth) but this happens with any language bundle active. I've turned off the Auto-pairing option in Preferences, and I am not using any form of auto-completion (to my knowledge),  but it without remedying the problem.  Needless to say this paring of characters is a nuisance in Forth, where I frequently want to write a colon on its own, without the equal-sign. 

Can anyone suggest where else I should look to turn this off?  I'm in Textmate 1.5.11

thanks in advance
- bruno

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Bruno Degazio
Professor, Faculty of Arts, Animation and Design
Sheridan College